U.S. Pat. No. 2,057,417 to Clapper, assigned to the assignee of this invention, discloses a riding mower having electrically driven cutting reels. An internal combustion engine drives a generator which supplies the electrical current for operating the electric motors that power the cutting reels. However, the drive wheels of the mower are mechanically driven from the engine. Accordingly, the engine must be continuously operated to drive the vehicle, which is undesirable in certain circumstances because of the noise and/or pollution generated by the engine.
U.S. Pat. No. 5,406,778 to Lamb et al. shows a riding mower in which the cutting reels and the traction drive are both electrically operated from batteries carried on the mower. There is no internal combustion engine provided on the mower, the only source of power being the batteries. While the mower is quiet during operation, it has limited range and usefulness due to the battery power source. This is particularly true because of the large energy drain imposed on the batteries to operate the traction drive.
Neither of the riding mowers disclosed in these patents is as effective as is desired for meeting the need for a quiet mower having adequate range and usefulness. The Clapper mower requires the use of an internal combustion engine sized sufficiently large to meet the peak horsepower needs of the mower, as when the mower is being driven at relatively high speed up a hill. Thus, the relatively large engine on the Clapper device generates a high level of undesirable noise. While the Lamb et al. mower may be quiet, it must be frequently recharged, limiting its usefulness.